PURPOSE: To obtain information about the order between a plurality of objects to be measured by calculating and displaying the time at which a time difference can be reduced based on the time difference between the objects until the objects reach each section after starting measurement and the number of remaining sections.

CONSTITUTION: Whenever a lap switch 4 (5) is pressed at every round after starting time counting by pressing a start/stop switch 6, the number rounds and lap time of a runner (partner) are displayed 2. The runner compares his own number of rounds (m) with that (n) of the partner by pressing a reference switch 7 and, when n m, calculates the remaining number of rounds of the partner and the difference between his own number (m) of rounds and that (n) of the partner. Then the runner calculates the split, namely, dummy when the runner reaches the number (n) of rounds on the assumption that the runner runs at the same lap time. Then the runner finds a value WIN by dividing the split difference calculated from the split and dummy at the number (n) of rounds of the partner by the remaining number of rounds. When the value WIN is positive (negative), a message indicating that the runner can be caught up by the partner (can catch up the partner) when the lap difference is reduced by WIN seconds is displayed 2.